Audio interface problem

I have sonar 5 producer and I have a tascam us-1800 audio interface. Sonar shows the drivers for all inputs and outputs,and i have chosen which to us,but when I play something I get no signal.Am I missing something. I have been using cakewalk products for number of years now,but not with an audio interface before. Just with a mixer through the sound card.I have never had this problem. I got an interface because its all I`ve heard is that its the way to go.Especially if you want to record drum sets and stuff that needs a lot of mics. I know I probably am just missing some stupid little step,but can`t figure that out. Help me please.

Yeah I am using old Xp. I have done all that other stuff and still nothing. Just doesn`t make any sense. Grrrrrrr

 Your not being clear about what is not happening. 
Not getting a signal would mean no INPUT. No sound in the headphones, no peak light action, track level meter does not move. Which channel are you using? A mike or are you using 9/10 instrument inputs? 
 
No sound is like Dave is saying, no OUTPUT which required different trouble shooting. 
 
Here's some OUTPUT stuff. 
My guess is your Master bus is set to Digital ( SPDIF) output. This happens to me when I load old projects that where made using an other interface. 
 
The US 1800 has 1/2 - 3/4 and a Monitor output. 
Use the monitor output for your studio monitors so as to utilize the control on the front. 
This control does not effect the headphone jack so it's easy to shut down room monitoring when tracking with a mike. 
And I would imagine you figured out the blend control too. This allows you to mix the input signal with the computers playback.
You'll find yourself using the 3 monitoring controls all the time. 
I run 1/2 and 3/4 into my Mixer for additional monitoring options. 
 
Don't use input echo with a Tascam while tracking audio as there will be around 12 ms or more delay from the Round trip latency, use the direct monitoring using the controls described above. When you upgrade to a newer system the RTL will drop to 6 or 7 ms but for me even that is to much while tracking. 
 

Yeah its an input problem.Peak light is not showing in Sonar. Peak comes on in interface just fine. And both mixers are fine.

Sorry it takes me so long to get back. My job schedule messes me up. So the 3 days that went by I wasn`t able to try anything.What other info could I give you cactus music to help me along?

If the drivers are showing up as you mentioned at the Sonar Edit Preferences Audio, then your Sonar is recognizing the drivers for the Tascam 1800. Playback-Recording select ASIO. Driver Settings, Playback Timing Master, choose the main outs there, and choose 1/2 or whatever as Record Timing Master. Devices, check the appropriate ins and outs for the Tascam.
 
The Tascam 1800 has a gain knob for each channel, make sure they are on. It also has a signal knob for headphones or speakers, check that too. If you have sound at the headphone jack at the Tascam, you just need to select the track inputs at your Sonar track pane.
 
At the track in Sonar be sure to check the correct track for your input at the Tascam. The tascam might say something like 2L 2R 2 Stereo? anyway...these are in pairs, like 1 L, 2 R, 1-2 Stereo etc...for the 8 or 12 inputs it has. If you are plugging directly into the Tascam at 9 or 10, check that you are going Hi-Z and not Mic or line or whatever it has. If you have a mic, plug that into #1 at the Tascam and check that too. But you have to choose the input at the track input in the track pane, and arm the track to record to see if you have a signal there. Insert an audio track, choose the input your using, and arm the track to record and test it.
 
You can also use an amp with a DI or a DI Box to go into the XLR channels at the Tascam without using the HiZ at 9 or 10. You can go into a effects processor, equipted with a DI or to a DI Box and then into the XLR's. This is how I do it. I never go staright into a HiZ at an interface. I am assuming you are playing guitar as your picture shows? You can also run Amp headphone jacks into the Tascam. Some amps and processors have a DI built into them.
 
Don't use a USB hub for the Tascam, and do use a direct 2.0 port. Turn your Phantom Power off if you are running in a guitar at the Tascam.